The present invention relates to coating compositions and systems, and more particularly, to spherosiloxane based coating compositions which are particularly useful for metallic surfaces, and methods of making and using the same.
Coatings for surfaces and, more particularly, metallic surfaces such as iron, aluminum, copper and stainless steel have been employed for years with the intention of providing such surfaces with enhanced protection against degradation and/or with aesthetical appeal. However, of the coatings which are known, many have been found to insufficiently bond to the desired metal substrate, especially under long term applications. Further, many of the coatings which are known often fail to endure post treatment processing of the surface such as those imparted during bending and shaping of the coated metal surface.
Still another perceived problem with many of the known coatings which are available and employed to coat metallic surfaces is that they fail to sufficiently protect the surface from contamination and corrosion.
Certain silicon based coatings, such as those disclosed in U.S. Pat. No. 4,714,632 by Cabrera et al., based on amorphous silicon dioxide are known to offer relatively good adhesion when applied as a diffusion coating to steel surfaces. However, it was noted that the porosity of amorphous SiO.sub.2 hampers the film's effectiveness for purposes of corrosion inhibition. Water and water soluble ions, which catalyze corrosion, are able to penetrate through the hydrophilic amorphous SiO.sub.2 framework, thus making the coated surface susceptible to corrosion.
It is, therefore, an object of the present invention to provide coating compositions which inhibit corrosion of the article which is coated.
It is another object of the present invention to provide a coating compositions which readily adhere to the surface to be coated.
Still another object of the present invention is to provide coating compositions which are substantially hydrophobic in nature.
It is yet another object of the present invention to provide coating compositions which are acid stable, and therefor resistant to chemical degradation.
Yet another object of the present invention is to provide coating compositions which can be functionalized, thereby allowing them to be used as a primer layer in conjunction with conventional coating technologies.
The composition and methods of the present invention preferably employ:
a spherosiloxane composition including silicon atoms which are capable of bonding with available oxygen atoms provided along the surface of the substrate to be coated.